Gaseous electric discharge device



w G. WELS GASEOUS ELECTRIC DISCHARGE DEVICE Filed Sept. 1, 1932 March 13, 1934.

INVENTOR ATTORNEY having thermionic Patented Mar. 13, 1934' UNITED STATES 1,951,112 GASEOUS ELECTRIC DISCHARGE DEVICE Giinter Wels, Berlin-Johannisthal, Germany, as-

signor to General Electric Company, a corporation of New York Application September 1, 1932 Serial No. 631,399

In GermanySeptember 16, 1931 1 Claim. (Cl. 176-124) The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to methods and means for starting and operating such devices electrodes.

In co-pending application, Serial Number 500,- 342, filed December 5, 1930 and being the invention of Marcello Pirani, Hans Ewest and Martin Reger, a starting and operating circuit for a gaseous electric discharge device having thermionic electrodes is disclosed wherein one terminal of said electrodes is connected across the terminals of a current source for the device, a high frequency apparatus is in operative relation to said device and is likewise connected across the terminals of said current source, and another circuit is connected across the other terminals of said electrodes to cause the heat ing of said electrodes. The switch for connecting the gaseous electric discharge device across the terminals of the current source, the switch in the heater circuit and the switch for the high frequency apparatus are hand operated switches. The object or the present invention is to provide a simple automatic means for operating the high frequency apparatus and the heater circuit switches in the starting and operating circuit of a gaseous electric discharge device. Still further objects and advantages attaching to the invention and to its use and operation will be apparent to those skilled in the art from the following particular description and from the appended claims.

In accordance with this object the invention comprises a thermostatic switch having the heater element thereof connected into one of the current leads for said device to control the operation of the switch in the heater circuit, and the switch in the high frequency circuit. The movable element of said thermostatic switch consists of a bimetallic strip or a column of mercury. In such circuit the closing of the main switch connected into one of the current inleads of the gaseous electric discharge device causes the heating of the thermionic electrodes, which emit electrons to ionize the gaseous filling, and the heaterfilament of the thermostatic switch. The heat radiations from said filament causes the movement of the switching element of said thermostatic switch'which interrupts the flow of current through said heating circuitand said high frequency apparatus in sequence. The interruption of current flow through the heating circuit throws the full line potential across the terminals of the device and this takes place 10 to 30 seconds after the closing of the main cur-' rent switch and the discharge path is heavily ionized during this period as the high frequency apparatus remains in the circuit after the heater circuit has been cut out of circuit thehigh frequency current is applied to the device when the full line potential is applied across-the terminals of the device by the cutting out of circuit the heater circuit. The electric discharge device is thus quickly and positivelystarted into operation by simple automatic means.

' I have found that gaseous electric discharge devices having a discharge path of 50 cm inlength are started into operation without the necessity of a highfrequency aparatus, the operating potential applied across the terminals of the devicewhen the heater circuit is cut out of circuit being suificient to start the device into operation after the thermionic electrodes have been brought to an electron emitting temperature by the heater circuit and have ionized the gas in the discharge path.

In the drawing accompanying and forming part of this specification two embodiments of the invention are shown in which Fig. 1 is a schematic View of one embodiment of the invention, and

Fig. 2 is a similar view of another embodiment v of I the invention.

Like numbers figures.

Referring to Fig. 1 the gaseous electric discharge device comprises a container 1 having a gaseous filling consisting of neon, for example. Thermionic electrodes 2 and 3 comprising a roll of electron emissive material, such as barium oxide, surrounded by a heater filament, such as a tungsten wire are sealed into said container 1. Said electrodes 2 and 3 are connected by leads 4 and 5 to the terminals 6 and 7 of an alternating current source of commercial voltage such as 110 or 220 volts. A choke coil 8 is connected into said lead 4. Said electrodes 2 and-3 are connected in series by lead 9 and said lead 9 has resistance 11 connected therein. Heater filament 15 of the thermostatic switch having glass container 16 is connected into said lead 5. Said container 16 is filled with an inert gas such as hydrogen. Said heater filament 15 surrounds a bimetallic strip 1'! having contact 18 attached to the movable .105 end thereof. The opposite end of said strip 17 is sealed into the wall of said chamber 16 and said lead 9 is connected thereto. A stationary contact 19 connected to said electrode 3 by lead 9 is sealed into said container 16 and said contact 18 is in no denote like parts in both the 8 contact with said contact 19 only during the heating up period of said electrodes 2 and 3. A hand operated switch 20 is connected into said lead 5.

When switch 20 is closed current flows through the above described circuit and heats" the electrodes 2 and 3 to an electron emitting temperature. simultaneously the heat radiations from said filament 15 heats bimetallic strip 17 which bends, moving contact 18 away from contact 19 to interrupt the flow of current through the heater circuit of said electrodes 2 and 3. Said electrodes 2 and 3 emitsufiicient electrons to ionize thegas in the discharge path therebetween before contact is broken between said contacts 18 and 19 which takes place approximately 10 to 30 seconds after switch 20 has been closed. The breaking of contact between said contacts 18 and 19 applies the full potential of the current source across the terminals of the gaseous electric discharge device which is suiiicient to start the device into operation where the distance between said electrodes 2 and 3 is approximately cm. or less.

The device illustrated in Fig. 2 is similar to that shown in Fig. 1 with the exception that the heater filament 15 is sealed into a container 21 having a bulb shaped upper chamber filled with an inert gas such as hydrogen and the lower part of said container 21 is a U shaped tube filled with mercury 22. Contacts 30 and 24 of lead 9 are sealed into said container 21 as shown and said contacts 30 and 24 are bridged by said mercury column 22 during the heating up period of said electrodes 2 and 3. A high frequency apparatus 25 is in operative relation to said gaseous electric discharge device and said apparatus 25 is connected by lead 28 to contact 23. Said apparatus 25 is connected by lead 29 to current lead 5.

When switch 20 is closed current flows through the circuit as described in connection with Fig. 1 and heater filament l5 heats the inert gas surrounding said fiiament 15, said gas expands foreing said mercury away first from contact 30 and then from contact 24 so that the line potential of the source is applied across the terminals of said gaseous electric discharge device when said high frequency apparatus 25 is operating. The gaseous electric discharge device is thus quickly and positively started into operation by closing switch 20. In this embodiment of the invention the distance between said electrodes 2 and 3 is greater than 50 cm. Current flows through the high frequency apparatus 25 over the leads 4, 9, the mercury column'22, the leads 28, 29 and 5 when switch 20 is closed. When the movement of the mercury 22 in the U -shaped tube has progressed until said mercury 22 is no longer in contact with said contact 24*of said lead 9 the high frequency apparatus 25 is cut out of circuit and remains out of circuit during the operation of the discharge device.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in'the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art Without departing from the broad spirit and 'scope of the invention, for exagnple, the thermostatic switch illustrated in Fig. 1 can be substituted for that illustrated in Fig. 2, where desired by providing said strip 17 with another set of contacts below the contacts 18 and 19 and connecting leads 28 and 29 of the high frequency apparatus 25 to said contacts in which case the operation of the thermostatic switch i1- lustrated in Fig; 1 will be the same as that illustrated in Fig. 2.

' What I claim as new and desire to secure by Letters Patent of the United'States is:-

In combination, an electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, one terminal of each of said electrodes being connected to a current source for said device, a starting circuit for said device comprising a high frequency apparatus connected to said current source, means for connecting said electrodes in series to said current source to heat said electrodes to an electron-emitting temperature and a termostatic switch connected into one of the current inleads for said device to makeand break the series connection between said electrodes and to cut into and out of circuit said high frequency apparatus, said series connection being broken before said high frequency apparatus is cut out oi. circuit.

GUNTER WELS. 

